Use "remain valid" in a sentence

1. If you are following along with this example by actually doing it, the numbers may have changed but the basic ideas and conclusions remain valid

2. While the key concepts of classical charting remain valid, many of its tools have been eclipsed by much more powerful computerized methods

3. Our arguments against the investor turning himself into an insurance company remain valid even if the insurance operations all told may prove profitable

4. • Validity period Specifies how long the certificate will remain valid